title: Dispersive liquid-liquid microextraction method based on solidification of floating organic drop combined with gas chromatography with electron-capture or mass spectrometry detection.
abstract: A simple dispersive liquid-liquid microextraction (DLLME) method based on solidification of a floating organic drop (DLLME-SFO) technique combined with gas chromatography/electron-capture detection (GC/ECD) or gas chromatography/mass spectrometry (GC/MS) has been developed. The proposed method is simple, low in cost, and of high precision. It overcomes the most important problem in DLLME, the high-toxic solvent used. Halogenated organic compounds (HOCs) in water samples were determined as the model compounds. The parameters optimized for the DLLME-SFO technique were as follows: A mixture of 0.5 mL acetone, containing 10 microL 2-dodecanol (2-DD-OH), was rapidly injected by syringe into the 5 mL water sample. After centrifugation, the fine 2-DD-OH droplets (8+/-0.5 microL) were floated at the top of the screwcap test tube. The test tube was then cooled in an ice bath. After 5 min the 2-DD-OH solvent had solidified and was then transferred into a conical vial; it melted quickly at room temperature and 3 microL (for GC/ECD) or 2 microL (for GC/MS) of it was injected into a gas chromatograph for analysis. The limit of detection (LOD) for this technique was 0.005-0.05microgL(-1) for GC/ECD and was 0.005-0.047 microgL(-1) for GC/MS, respectively. The linear range of the calibration curve of DLLME-SFO was from 0.01 to 500 microgL(-1) with a coefficient of estimation (r2)>0.996 for GC/ECD and was from 0.02 to 500 microgL(-1) with a coefficient of estimation (r2)>0.996 for GC/MS.
authors.affiliation: Department of Chemistry, National Tsing Hua University, Hsinchu 30013, Taiwan.
authors.forename: Mei-I
authors.initials: MI
authors.lastname: Leong
authors.forename: Shang-Da
authors.initials: SD
authors.lastname: Huang
mesh_terms: D002138:Calibration; D002722:Chlorobenzenes / Q000032:analysis*; D002849:Chromatography, Gas / Q000191:economics / Q000379:methods*; D007851:Dodecanol / Q000032:analysis*; D004784:Environmental Monitoring / Q000379:methods; D008401:Gas Chromatography-Mass Spectrometry / Q000191:economics / Q000379:methods; D012492:Salts / Q000737:chemistry; D012680:Sensitivity and Specificity; D012997:Solvents / Q000737:chemistry; D013750:Tetrachloroethylene / Q000032:analysis*; D013997:Time Factors
chemical_list: D002722:Chlorobenzenes; D012492:Salts; D012997:Solvents; D007851:Dodecanol; C031294:chlorobenzene; D013750:Tetrachloroethylene